Consolidated Statements Of Stockholders' Equity (Parenthetical) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Consolidated Statements Of Stockholders' Equity [Abstract]
Issuance of common stock, shares	151,150	113,223	439,304
Issuance of deferred stock units, shares	47,506	2,767	34,947
Special cash dividend, per share		$ 1.50
Purchase of treasury stock, shares	33,856	53,879